Why Evolution is a Bad Explanation for Human Behavior

Nearly every day I hear, read, or see the latest news story about how the human brain is hard-wired to make all humans act in one particular way or another. These stories annoy me because:

They emphasize that all humans are the same and ignore the fact that we’re all unique and, to a large degree, unpredictable.

They imply that humans are unlikely to change or deviate from one another.

They repeatedly claim we’re all hard-wired despite the fact that the human brain has NO WIRES.

Even worse, at the bottom of most of these “Your brain is hard-wired” stories is a mythical evolutionary explanation. This annoys me even more . . . because when it comes to everyday human behavior, evolution makes for very bad explanations. But if you’re listening to what pundits and scientists say in the media, you’d be inclined to believe the opposite of what’s really true about humans.

For mysterious reasons, many scientists—especially evolutionary scientists—want to put humans in a box. They suggest and imply and assert that human behavior is predictable. But the truth is that—apart from breathing—there are very few predictable human behaviors. As decades of controlled psychological experiments have shown, even under laboratory conditions where little choice is possible, scientific predictions typically account for no more that 30-40% of the variation in human behavior. This means that humans are 60-70% unpredictable . . . even under highly controlled conditions.

Aside from being mostly wrong, simple evolutionary and biological explanations for human behavior also often are translated into messages that are generally unhealthy for society. Let’s take one big example.

An especially popular media and science topic is male sexual behavior. Theargument usually goes like this: Over millions of years males have become hardwired to be attracted to fertility and novelty in sexual partners. This is because . . . the argument continues . . . males seek to perpetuate their gene-pool. This is why, they say, males are attracted to younger females who exhibit signs of reproductive health. This also explains why males—especially young males—are driven to have sex with multiple female partners.

Given current U.S. social problems—think sexual assault and high divorce rates—it makes little sense to promote the mostly false ideas that males seek sexual novelty to perpetuate their gene pool. This information is unhelpful to women who want safe and stable relationships with men and it’s unhelpful to the majority of men who—in contradiction to evolutionary theory—want safe and monogamous intimate relationships with women (or other men).

Most of the time, most males engage in sexual behavior that’s not at all designed to spread their seed or perpetuate their gene pool. Young men are often strongly motivated to NOT get their girlfriends pregnant. Recent data indicate that many young men are NOT especially interested in engaging in indiscriminate sexual behavior.

Even in a 2011 research study at Syracuse University, 333 undergraduate males apparently hadn’t gotten the memo about being hardwired to want sex with novel partners. When asked, whether they could “. . . imagine themselves enjoying casual sex” these young men showed an average response that was largely in the “undecided” range. Think about that: males from 18-22 years-old at Syracuse University couldn’t really decide if they might enjoy casual sex. This is good news. And it’s not consistent with evolutionary-based myths about contemporary young men.

In the same study, 300+ Syracuse University women reported—in direct contradiction to evolutionary theory—that they had been engaging in casual sexual encounters at approximately the same rate as the males.

And so next time you hear or read or view a media story about how millions of years of evolution explains why human males or females behave one way or another, remember that many immediate conditions can and do override evolutionary-based predictions. Evolution is a generality that may or may not apply to a single organism living in the 21st century. Evolution does not trump choice. And that’s the point: Your choices tomorrow will have much more to do with the situations you’re facing today (and that you’re anticipating tomorrow) than they’ll have to do with yesterday.

7 thoughts on “Why Evolution is a Bad Explanation for Human Behavior”

Very well and engagingly argued, John — as I would expect. I agree that some evolutionary psychologists go too far with their claims — that is, they go beyond what the evidence will support. But I suspect you would agree that this doesn’t discredit the entire enterprise. It would be very surprising if thousands of generations of evolution hadn’t left SOME stamp on human behavior, especially in the arena of sexuality, where we would expect genetic competition to be particularly acute. Assuming we could weed out the scientifically unsupported claims of genetic determinism, I’d guess that we would be more successful, over the long haul, in discouraging socially undesirable behavior if we acknowledge that some of it does have evolutionary roots than we would be if we steadfastly deny those roots. That would seem to be as unscientific as the other extreme, and I’m therefore confident that that isn’t your position.

Thanks for your comment on my evolutionary psychology blog. Your comment is so balanced and reasonable that I have hardly any response to it. . . other than to say, of course, I am in agreement with you. My hope for the future of evolutionary psychology is for it to begin to focus on how our current and future knowledge of these “softer-wired” social/psychological processes can help us to take a more creationist attitude toward evolution. That is to say, I hope our knowledge of evolution can help make all of us even better in the future. I suspect this has broad applications to our discussion the other night about methods for fostering community.

A lot of this stuff is speculation and is not scientific or testable – that’s a fair cop and I totally agree with you. However we are “hard wired” (figuratively speaking) in some ways. We do not learn or decide to feel pain for instance, we are hard-wired to feel it. While yes, it is true that some people don’t feel sense pain for various reasons, some of them genetic, if a biologist said “humans are hard-wired to feel pain” it would be reasonable to assume he/she is speaking generally and is simply talking about pain or biology and not talking about inability to feel it. If I say something about men I am not making a huge error by not mentioning that women also exist.

Good point. Pain is a great example of something that very likely has deep evolutionary roots and is consequently “figuratively” hard-wired. Most of my annoyance doesn’t really come from evolutionary theory, but for using it to explain and therefore excuse specific social behaviors. For example, “Boys will be boys” tends to be a way for us to excuse males for certain behaviors and, I think, then sets the bar too low regarding expectations for boys to engage in civil behavior and emotional communication–both of which boys are quite capable of.

I hope this makes sense and I hope your New Year is off to an excellent start.

I agree that while some things are in-born (there are obvious physical differences between genders and are bound to be mental and behavioral differences too) I am not sure how much of it is in-born and how much of it seems in-born because it’s deeply engrained in us as the social norm. It’s also worth mentioning that a cornerstone part of evolution is variation, which means that someone someone, somewhere will defy any stereotype just as surely as someone will fit it, and that things like “men are agressive” and “women are not” (to use a vague, lazy example) are only true generally and many men and women will be the reverse – which is necessary for evolution to work at all.

I agree with the thrust of this blog piece, yet I would put it slightly differently: Evolution makes a poor excuse for human behavior. The PTSD sufferer did not choose to have recurring nightmares. The individual who had strep throat as a child did not choose OCD.

I find that evolution can go a long way in explaining these outcome and a long way in lessening the doubt and guilt clients often feel about their symptoms. The important distinction is noting the difference between using evolution as an explanation versus using it as an excuse.

You make a fabulous point and I certainly didn’t mean to minimize the important ways in which evolutionary theory can help explain various troubling human behaviors. I really like your emphasis on excusing vs. explaining, especially because the way in which you articulate it makes it a very nice way for individuals to be kinder to themselves regarding specific distressing behaviors they may be experiencing. Well-stated.

Also, I’m glad you found the MSE post helpful and will look forward to meeting you in Cincinnati next week!